1. Field of the Invention
The present invention relates to an amplifying device and offset voltage correction method.
2. Description of the Background Art
In a differential amplification circuit, imbalance normally occurs in current flowing through the circuit due to a mismatch in differential pair transistor characteristics or the characteristics of an active load connected to the differential pair transistors, and offset voltage arising from the current imbalance is generated. When the offset voltage is high, it may cause error and affect the circuit operation, because of which offset voltage reduction is carried out.
For example, an amplification circuit wherein differing fixed reference voltages are applied to the differential pair transistors, and offset voltage is uniformized over a predetermined temperature range based on bias current output from one transistor of the differential pair, has been proposed as existing technology.